290 NOSTOCHINEiE. 



Ulva pisiformis Hudson. Conf. pisurrif Flor. Dan.; 

 Harv. in Hook. Brit. Flor. p. 400. ; Harv. in Manual, 

 p. 185. ; Meneghini, Monographia Nostocliinearum, 

 p. 110. 



Ilab. In rivulets and fountains, attached to stones, &c. 

 Appin : Captain Carmichael. Pools near Barmouth and 

 Llyn Coron, near Anglesea : Mr. Ralfs. Co. Wick- 

 low : Mr. Moore, 



-i^L^c^i (( Fronds from half a line to two lines in diameter, globular, 

 -c , firm, smooth, solid, heaped on each other like a parcel of small 



shells. Internal filaments rather thinly scattered through the 



mass." — Carm. 

 J/ 7, " This species dried and again moistened sometimes emit a 



most grateful violet odour, as though it were a species of 



Chroolepis, and such as no other Alga of the family of Nos- 



tocliinecB presents." — Menegh. 



The filaments are moniliform, and exactly correspond with 



those of Nostoc foliaceum in size, the young state of which 



species, as it agrees with it also in habit, it may eventually 



prove to be. 



5. Nostoc vesicaeium D. C. 



Char. " Frond globose, plicated, greenish yelloic, the internal 

 viscid mucus escaped, vesicceforyn, cartilaginous. Filaments 

 curved, slender, ivith cells twice as large, thickly interspersed 

 and terminal.'^ — Menegh. 



D. C. Flor. Fr. vol. iii. ; Harv. in Hook. Br. Flor. p. 399. ; 

 Harv. in Manual, p. 184.; Ag. Syst. p. 19.; Meneghini, 

 Monographia Nostochinearum, p. 108. 



Hab. Boad-side, near Perth : G. A. W. Arnott, Esq. 



" The diameter of the frond varies from a milHmetre to an 

 inch. The colour in the smaller fronds obscurely green, verges 

 in the larger to a yellowish brown. Substance firm, cartilagin- 

 ous, including a fluid viscous juice : afterwards, the gelatinous 

 substance having escaped, empty, vesicaeform, membranaceous ; 



